aframe2

My Feedback: (5)

I have a Zenoah G-26. I can't get the carb to draw fuel and found out that the rectangle screen that is behind the idle screw
is stopping the flow of fuel from the gas tank to the carb. My question is, can I run the engine without this screen? There is another
smaller round screen behind the rectangle one. Both of the screens are clean, the engine is brand new. I cleaned the screen and
installed it back in its original position and the flow of fuel is stopped.

w8ye

My Feedback: (16)

The area shown in your pictures normally just has the round screen

The other screen is behind a Welch plug on the other side of the carb

Antique

My Feedback: (4)

Only screen you can even see in that carb is round...It is very fine and can be taken out and cleaned..Put it back and see that your fuel is filtered before it gets to the screen...There are no other user serviced screens in a Walbro, no where, no way...If you're trying ot push fuel through the fuel inlet, it can't be done...The pump in the carb does it when the engine is running...Hook up the fuel line with the cover off and you'll see where the fuel goes, to the screen but only when the cover is on...The square thing in the picture is the pump diaphragm,

aussiesteve

If what you are referring to as the "rectangle screen" is the tan colored thing. I suggest you take it to a shop to get them to show you how it all works.

That tan colored rectangular item item is the fuel pump diaphragm and the 2 small flappers are the fuel pump valves. If you assemble the carb wrong, it will not work too well.

As Antique mentioned, you won't be able to push fuel through the inlet manually.

You mention the engine is new, If you are trying to get the first prime of the engine, flood a little fuel into the canber you are showing in your pics then put the carb cover back on (with the fuel pump diaphragm in the corect position).

I notice a couple of other things in the pics that concern me a little.
1 - the push on ball joint for the throttle - these are not the most ideal for use on a gasser as they can wear fairly quickly and fall off (always at the worst possible time).

2 - The idle stop screw - (the pointed screw on the cover) - remove it completely - they are not a useful thing to have on an RC plane.

3 - Is that fuel tubing silicone tubing? (as in for glow fuel?) If so - remove it as gas will eat it out fairly quickly.

Truckracer

My Feedback: (19)

Fuel tubing sure looks like silicone too me!

kerwin50

Good call truckracer he is head for big problems with that fuel line.

av8tor1977

My Feedback: (6)

Heck, they regulate everything else, why don't they regulate the use of screwdrivers and other mechanical tools??

AV8TOR

aussiesteve

Hey av8tor, I agrre with the intent of your post but in a closely related issue, There was actually a push towards something along those lines Here in Aus a few years ago. Teh push was by a Motor Trade associated group who's reasoning was along the lines of.

People can mess with the brakes or suspension on their car, get it wrong and kill others. Only licensed people should be allowed to work on (and have access to) safety critical components.

It never went through but it was close ( I think the Plumbers and Electricians complained about not being able to service their own cars ). - Be careful what you wish for

Truckracer

My Feedback: (19)

aussiesteve mentioned the fuel line, I just agreed.

Truckracer

My Feedback: (19)

A couple of years back a law (regulation?) went through my states legislature that required all electrical work done a farm to be done by a licensed electrician. This has largely been ignored by a farm population that in many cases knows more about whats going on their farm than a hired electrician would. Frankly, if this law was followed 100%, there wouldn't be enough electricians around to get all the work done. Farming is high tech these days and requires lots of wiring, controls, etc. in various forms. Sometimes a real electrician is called for but many times the farmers have more than enough skills for the task. Just another law run amuck!

captinjohn

I agree too...anyone else????

Tired Old Man

My Feedback: (1)

Only things wrong I see here are in qualifications. The owner of the engine is as yet unqualified to operate it. Start with that and work forward.

Read the newbies to gas engine sticky, all of it, and then come back with questions.

aframe2

My Feedback: (5)

You are right, I am unqualified to operate this engine. That is why I am asking questions. I would venture to guess that at one time in your life you too were
unqualified. I need answers to my questions, not judgement. I came to this forum for advice and answers to things I don't understand. If you have no
positive criticism for me then you need not reply. I here enough from prima donnas in my everyday life. Thanks to all you posters that gave me positive
criticism. Aframe2

RCVFR

My Feedback: (7)

aframe2 you are in the right place to get information on gassers. Look at the top of this forum for a "sticky" on information for newbies to gassers. This is a comprehensive compilation of good information put together by contributors to be helpful to you and others. If you need some clarification on some of that information, I am sure you will find willing help from many here. People who give a lot of help to others like to see that the inquiries come from someone who has at least made some effort at personal research. Welcome.

Antique

My Feedback: (4)

Put the cover back on the carb..Take the cover off the other side, 4 screws...A gasket and a diaphragm with a metal center...You will see a small lever in the center of the cavity under the diaphragm...The lever controls a needle that admits fuel into the carb...Blow into the fuel line...You should not be able to get air into the line unless you depress the lever to lift the needle on the other end....This is normal...If you can get air through the line without depressing the lever the carb is incorrectly assembled.....Take it to a small engine shop to have it corrected....A Walbro operating correctly will draw fuel 4 feet straight up when choked with a thumb or finger....It takes at least 8 lbs presssure to force fuel through the fuel line, NO ONE can possible blow that hard....If it still doesn't work after the carb is correctly assembled you have a problem with the pulse impulse from the crankcase....The pulse impulse has nothing to do with pumping when the engine is not running, it only works when the piston is going up and down after the engine starts...Choking pulls fuel from the tank, running does the pumping otherwise....
Get some Tygon or neoprene fuel line, the silicone will NOT work...

av8tor1977

My Feedback: (6)

I couldn't resist the post I made at the time, but I do feel a bit guilty about it. Thanks for making a more appropriate post Ralph.

AV8TOR

aframe2

My Feedback: (5)

Thanks for the information. I got the engine running. I've read the sticky on Gassers for newbies numerous times. I am having a transition problem from Idle to
full throttle, but I am reading all of the advice I can find on this forum, and am certain I will get it right. Thanks again for your advice. In the future I will be
asking more questions you may find simple, may even involve screwdrivers or other mechanical tools. Aframe2

av8tor1977

My Feedback: (6)

If the response from idle is slow and perhaps "burbly", the low speed needle is too rich. Make a small adjustment (Like 1/8 turn or less) clockwise and try it again. If the response from idle is an abrupt hesitation, or the engine quits, the idle is lean. In that case turn the low speed screw out a very small amount and try again. Often times the idle mixture has to be a bit richer than ideal in order to get a good throttle response. Adding exponential to your throttle channel to slow down the initial throttle movement can help this if your radio is able. (It can also be solved by throttle linkage geometry.)

Note that one needle affects the other on carb adjustments, so after changing the idle mixture you will need to re-check the top end mixture.

Good luck,
AV8TOR

GerKonig

And then when the barn burns down, and the insurance adjuster finds out that the job was not done by an electrician, what happens?

Around here you cannot do a thing with gas in your home (like for a range, whatever) unless you are licensed.

Gerry

Tired Old Man

My Feedback: (1)

Sir,

I hate to instigate an arguement, but you completely missed the directive I provided and became angry with the obvious. Most all the information you need is contained within that sticky. It has already been written and vetted many times over. Far faster and easier for you to take the time to read it than it is for everyone to start over, redundantly writing the same things for the umpteenth time. Once you've read that sticky you could/should return and pose questions from a position of enlightenment for greater clarification. You've already asked a dumb one in your first post. You don't have to ask another question based upon a lack of information. You could of course choose to by failing to take advantage of a wealth of previously published information designed and intended to assist people just like you.

If you cannot follow directions now you are doomed to failure and no amount of advice will ever be able help you to achieve success.

I am not being critical, but do appear to be stating fact based upon accurate observations. You have already elected to ignore some very good advice and instead chosen to become indignant when presented with reality.

aframe2

My Feedback: (5)

No one is twisting your arm to reply to my post tired old man. I've seen you slam other people on this forum. Apparently you think you run things. If you don't like my
question don't reply. Get a life.

Truckracer

My Feedback: (19)

There is a time and place for the licensed contractor, be it electrical, plumbing, etc. but in many cases they are simply not required or needed. I work around and even employ many forms of contractors as subs. Many are no more knowledgeable than a good do-it-yourselfer. Some do terrible work even though they are licensed but I suppose that would be OK by an insurance company in the event of a mishap?! I would hope a good insurance adjuster would judge the overall quality of work performed rather than just noting whether the person doing the work was licensed. Frankly, it shouldn't even be an issue unless a mishap is traced directly to faulty work.

Likewise and related more to our hobby, I would guess that many people that frequent this forum are more knowledgeable about small gas engines than many people who call themselves mechanics in small engine shops. I have certainly run into enough of the bad kind over the years. Yes, there are the good ones out there too, just to give them their due.

aframe2, just about every question you have asked has been answered in the sticky up top or has been answered very recently here in this forum and probably by a regular such as TOM. Should he go back and do the searches and post links to every one of your questions just so you don't have to do any of the work yourself? I think not, he has paid his dues here many times over!

aussiesteve

T.O.M has certainly taught me a thing or two over the years and I am close to the same age and years of messing with engines (in general) as he is. IMHO ALL advice is good, it is how it is evaluated and used that makes the difference.

Here's a possibility - You could have a fuel priming issue because you are using the wrong oil or ratio. Maybe it is gumming everything up. Which oil and at what ratio is being used? And why is that? it is very important to get it right

Richard39

My Feedback: (14)

Aframe2.... I really appreciated your pictures and the infomation that you received.... hang in there and have fun... this not a job for most of us....

Antique

My Feedback: (4)

If you think the screen is the problem just leave it out...But it really isn't...